It is assumed that the mechanisms that regulate long term systemic arterial blood pressure depends on a "setpoint" (or a narrow "set range") of an ideal arterial blood pressure that is recognized as normal by the kidney. It is hypothesized that the numerical value of that set point is not an intrinsic renal property but that it is acquired (learned) during a time that a nonrenal mechanism for the regulation of systemic arterial blood pressure has overriding control. The research plan outlines several methods by which systemic arterial blood pressure can be changed. The experiments are designed to test the prediction that such changes will lead to permanently altered set points in the renal control of arterial pressure. The experimental animals are expected, therefore, to become permanently hypertensive or hypotensive, without permanent changes in plasma renin activity.